Tip the onion, leeks, bay leaves and ham into a slow cooker. Pour over the hot vegetable stock and cook on high for 2 hrs or low for 6 hrs. If you have an uncooked gammon joint, you can use this, but you’ll need to cook the soup for an additional 45 mins on high or 2 hrs on low.

Remove the ham and set aside. Pour the peas into the slow cooker and cook on high for 30 mins more until the peas are cooked through. Meanwhile, shred the ham. If it has cooled enough, you can do this with your hands, or use two forks.

Remove the bay leaves from the soup and discard, then transfer the soup to a blender and blitz. Once completely cool, the pea soup (without the ham) can be frozen for up to three months. Defrost completely in the fridge overnight, then reheat in a pan until piping hot to serve. Season to taste, then divide between bowls and scatter some of the shredded ham over each bowl before serving.